examples/guest-vcpus/guest-vcpu-daemon.py

   1 #!/usr/bin/env python
   2
   3 import libvirt
   4 import threading
   5 from xml.dom import minidom
   6 import time
   7 import sys
   8 import getopt
   9 import os
  10
  11 uri = "qemu:///system"
  12 customXMLuri = "guest-cpu.python.libvirt.org"
  13 connectRetryTimeout = 5
  14
  15 def usage():
  16     print("usage: "+os.path.basename(sys.argv[0])+" [-h] [uri]")
  17     print("   uri will default to qemu:///system")
  18     print("   --help, -h   Print(this help message")
  19     print("")
  20     print("This service waits for the guest agent lifecycle event and reissues " +
  21            "guest agent calls to modify the cpu count according to the metadata " +
  22            "set by guest-vcpu.py example")
  23
  24 class workerData:
  25     def __init__(self):
  26         self.doms = list()
  27         self.conn = None
  28         self.cond = threading.Condition()
  29
  30     def notify(self):
  31         self.cond.acquire()
  32         self.cond.notify()
  33         self.cond.release()
  34
  35     def waitNotify(self):
  36         self.cond.acquire()
  37         self.cond.wait()
  38         self.cond.release()
  39
  40     def addDomainNotify(self, dom):
  41         self.doms.append(dom)
  42         self.notify()
  43
  44     def closeConnectNotify(self):
  45         conn = self.conn
  46         self.conn = None
  47         conn.close()
  48         self.notify()
  49
  50     def setConnect(self, conn):
  51         self.conn = conn
  52
  53     def hasConn(self):
  54         return self.conn is not None
  55
  56     def hasDom(self):
  57         return len(self.doms) > 0
  58
  59     def getDom(self):
  60         return self.doms.pop()
  61
  62     def setDoms(self, doms):
  63         self.doms = doms
  64
  65
  66 def virEventLoopNativeRun():
  67     while True:
  68         libvirt.virEventRunDefaultImpl()
  69
  70 def handleAgentLifecycleEvent(conn, dom, state, reason, opaque):
  71     if state == libvirt.VIR_CONNECT_DOMAIN_EVENT_AGENT_LIFECYCLE_STATE_CONNECTED:
  72         opaque.addDomainNotify(dom)
  73
  74 def handleConnectClose(conn, reason, opaque):
  75     print('Disconnected from ' + uri)
  76     opaque.closeConnectNotify()
  77
  78 def handleLibvirtLibraryError(opaque, error):
  79     pass
  80
  81 def processAgentConnect(dom):
  82     try:
  83         cpus = dom.metadata(libvirt.VIR_DOMAIN_METADATA_ELEMENT, customXMLuri,
  84                 libvirt.VIR_DOMAIN_AFFECT_LIVE)
  85         doc = minidom.parseString(cpus)
  86         ncpus = int(doc.getElementsByTagName('ncpus')[0].getAttribute('count'))
  87     except:
  88         return
  89
  90     try:
  91         dom.setVcpusFlags(ncpus, libvirt.VIR_DOMAIN_AFFECT_LIVE | libvirt.VIR_DOMAIN_VCPU_GUEST)
  92         print("set vcpu count for domain " + dom.name() + " to " + str(ncpus))
  93     except:
  94         print("failed to set vcpu count for domain " + dom.name())
  95
  96 def work():
  97     data = workerData()
  98
  99     print("Using uri: " + uri)
 100
 101     while True:
 102         if not data.hasConn():
 103             try:
 104                 conn = libvirt.open(uri)
 105             except:
 106                 print('Failed to connect to ' + uri + ', retry in ' + str(connectRetryTimeout)) + ' seconds'
 107                 time.sleep(connectRetryTimeout)
 108                 continue
 109
 110             print('Connected to ' + uri)
 111
 112             data.setConnect(conn)
 113             conn.registerCloseCallback(handleConnectClose, data)
 114             conn.setKeepAlive(5, 3)
 115             conn.domainEventRegisterAny(None,
 116                                         libvirt.VIR_DOMAIN_EVENT_ID_AGENT_LIFECYCLE,
 117                                         handleAgentLifecycleEvent,
 118                                         data)
 119
 120             data.setDoms(conn.listAllDomains(libvirt.VIR_CONNECT_LIST_DOMAINS_ACTIVE))
 121
 122         while data.hasConn() and data.hasDom():
 123             processAgentConnect(data.getDom())
 124
 125         data.waitNotify()
 126
 127 def main():
 128     libvirt.virEventRegisterDefaultImpl()
 129     libvirt.registerErrorHandler(handleLibvirtLibraryError, None)
 130
 131     worker = threading.Thread(target=work)
 132     worker.setDaemon(True)
 133     worker.start()
 134
 135     eventLoop = threading.Thread(target=virEventLoopNativeRun)
 136     eventLoop.setDaemon(True)
 137     eventLoop.start()
 138
 139     while True:
 140        time.sleep(1)
 141
 142 if __name__ == "__main__":
 143     try:
 144         opts, args = getopt.getopt(sys.argv[1:], "h", ["help"])
 145     except getopt.GetoptError as err:
 146         print(str(err))
 147         usage()
 148         sys.exit(2)
 149     for o, a in opts:
 150         if o in ("-h", "--help"):
 151             usage()
 152             sys.exit()
 153
 154     if len(args) > 1:
 155         usage()
 156         sys.exit(1)
 157     elif len(args) == 1:
 158         uri = args[0]
 159
 160     main()